Insulator



Aug.

C. LE G. FORTESCUE INSULATOR Filed June 29, 1922 INVENTOR Charles L2G.Forteeoue.

WITNESSES ATTbRNEY distorted by Patented Aug. 2, 1927.

CHARLES LE G. FOBTESCUE,

OF PITTSBOBGH, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A. CORPORATION 01 PENNSYL- VANIA.

INSULATOR.

Application filed June 29, 1922. Serial No. 571,752.

My invention relates to insulators and particularly to insulators of the suspension type.

One object of my invention is to so assemble the parts of an insulator while under stress as to preclude distortion and other injury thereto when subjected to load forces.

Another object of my invention is to provide a high-potential suspension insulator that shall be simple and durable in construction and effective in its operation. 1

It has been heretofore suggested to provide tubular insulating structures having core members in which the core member sustained the principal load forces and the outer tubular shell protected the core. Where the tubular shell is of refractory material and the core member of iron, fiber or other suitable material, the differences in elasticity and thermal expansion cause fracture of the shell, separation of the parts of a sectional shell and separation of the ends of the shell from the terminal members. These failures have been difficult to overcome, with the result that such insulators, which are very satisfactory, from the standpoint of strength, have not gone into extended use.

In practicing my invention, I provide a tubular insulating structure having a core member that is subjected, during assembly, to forces comparable to the load forces which it is adapted to sustain. It is thus the normal amount which it would assume under load, and, while the core member is so distorted, a member is inserted between the ends of the insulator to prevent complete retraction of the core whe the distorting forces are removed. 1

By means of the arrangement of parts, the core member is adapted to more directly take up the load forces and the tubular shell is not subjected to the stresses which ordinarily injure it and break the enclosing seal which it provides for the core member.

The single figure of the accompanying drawing is a longitudinal or'side view, partially in section and partiallyin elevation, of a suspension insulator embodying my invention.

The insulator of my invention comprises, in general, metal terminal members 1 and 2, insulating end members 3 and 4, an intermediate member 5, a core member 6 and mem-.

'tions.

firs 7 and 8 on the ends of the core memr. The members 3 and 4, preferably constructed of refractory material, are of tubular or cup-shape, over the closed ends of which the terminal members 1 and 2 are secured, as by cementing, in a usual and well known manner. The members 3 and 4 may also be provided with petticoat portions 9.

The core member 6, which may be of wood, fiber, metal or any other suitable material, is preferably constructed of wood having frusto-conical ends over which the members 7 and 8 are swaged in position. Bodies of cement 1O secure the members 7 and 8 in position in the members 3 and 4.

The adjacent ends of the members 3 and 4 are shaped or flanged to provide closely adjacent edges 11 and shoulders 12 between the latter of which the member 5 is disposed.

The member 5, in this construction, constituting a petticoat, is divided or diametrally split to permit it to be placed in position after the members 3, 4 and 6 have been assembled. The latter may be so proportioned that, when integrally assembled, the edges 11 of the members 3 and 4 are in engagement.

After the assembly of the members 1, 2, 3, 4 and 6, the insulator is subjected to tension forces comparable to the maximum load forces which the insulator is adapted to withstand. This action is also preferably efiective under the approximate highest temperature service conditions, so that the parts are expanded by heat and. mechanically stretched to the maximum limits of distortion that occur under service condi-' When so expanded, the edges 11 and the shoulders 12 are separated to admit the halves of the member 5 which is of such thickness as to substantially fill the increased spaoe between the shoulders 12.

When the forces extending the insulator are released, the member 5 prevents the return of the parts to the initial positions thereof, so that when the insulator 1s installed under service conditions and again subjected to tension, there will be practically no additional stresses tending to crack the refractory members3 and 4 or to separate them I the appended claims.

I claim as my invention: 1. An insulator comprising terminal members, a tensioned member connected therebetween and a second member disposed between said terminal members, said second member being permitted of operative positioning by reason of displacement of said terminal members in response to the tensioning of the tensioned member.

2. A tubular insulator structure comprising end members, a tensioned core member secured adjacent to its ends to said end members and a member disposed between the end members under compression therefrom, said core member being tensioned by pulling said end members oppositely to permit the reception of said compression member.

3. A tubular insulator structure comprising end members of cup-shape, a tensioned core member for the tubular structure secured at its ends in said cups and a mem-j ber disposed in position between said end members under compression therefrom, said core member being tensioned by pulling said end members oppositely to permit the reception of said compression member.

4. A tubular insulator structure comprising end members of cup shape, a tensioned core member for the tubular structure secured at its ends in said cups and a diametrically divided member surrounding the core member between said 'end members under compression therefrom, said core member being tensioned by pulling said end members oppositely to permit the reception of said compression member.

5. A tubular insulator structure comprising end members of cupshape, a tensioned core member for the tubular structure secured at its ends in said cups, and a member,

oppositely to permit the reception of said compression member.

In testimony whereof, I have hereunto' subscribed my name this 23rd day ofJune 1922.

CHARLES LE G. FORTESCUE. 

